Love at first sight is wonderful — but getting “Married at First Sight,” not so much.

A Queens woman, who went on a cable reality show in which two strangers get hitched moments after meeting, has filed court papers saying her random groom threatened to kill her and her family.

Jessica Castro, 30, claims her experiment in whirlwind weddings on A&E’s “Married at First Sight” went horribly wrong after her groom, Ryan De Nino, of Staten Island, made his creepy murder vow in March.

“I will break you into f—ing pieces,” the 29-year-old business consultant raved, according to a Queens Family Court petition filed Friday. “I will break your dad into pieces. I will make your whole family disappear — and your f—ing dog-ass sister’s boyfriend.”

Then, while taping a reunion show in May, De Nino allegedly made a slip-up reminiscent of millionaire murder suspect Robert Durst’s admission that he “killed them all” on the HBO documentary “The Jinx.”

According to the petition, De Nino was caught on a live mic saying, “She’s f—ing dead. When I get back to Brooklyn, she’s f—ing dead, this girl.”

Castro, a law firm receptionist, and De Nino appeared on Season 2 of the show. After getting married in December, they proceeded to live together for several weeks, in which the producers taped the conflicts that would naturally arise from two strangers coupling.

Photo: A&EThey broke up in February, when Castro says she caught De Nino cheating on her on Valentine’s Day, the papers state.

The show’s producers took De Nino’s May reunion show death threat so seriously that they provided Castro with security personnel, according to the filing.

De Nino is facing Family Court charges of harassment, menacing and stalking. Court referee Julie Stanton ordered De Nino to stay away from his wife until their hearing on July 13.

De Nino did not return calls for comment, but he posted on Instagram to say he was “disgusted” by the allegations.

A photo posted by Ryan De Nino (@ryandenino) on Jun 13, 2015 at 2:46pm PDT

Castro’s lawyer, celebrity divorce attorney Marc Rapaport, declined to comment specifically on the order of protection but said his client is “considering all her legal options including potential claims against A&E.”

Rapaport is subpoenaing A&E because he suspects the show’s executives knew about De Nino’s volatile nature yet cast him anyway to add sensationalism to the series.

A spokesman for the show’s producers, Kinetic Content, said: “We don’t know all the details and can’t comment on the specifics.

“What we can say is that unfortunately, couples on the show can go through real divorces, and divorce can often be difficult.”

The statement added that all couples go through “extensive background and psychological checks.”

“We can’t control how they behave or govern their actions after production,” the spokesman said.